Development of a methodology for paint dust waste energetic valorization trough RDF production

Abstract

Industrial activity of aluminum surface coating, namely by electrostatic painting with a polyester powder based resin, generates a significant array of wastes. Among these wastes, paint dust is classified as 08 01 12 on the European List of Wastes. As consequence of the inexistence of adequate treatment routes for its correct management, this waste is currently landfilled, without any energy and / or material recovery. Therefore, the development of proper waste management technologies in line with the environmental policies is imperative in order to improve the industrial competitiveness and to preserve the natural resources. In the present work, RDFs (Refused Derived Fuel) were produced, as pellets, for energetic valorization. These experimental RDF pellets were manufactured by mixing the industrial paint dust with sawdust (1.5 and 3%) and with paperboard (1.5%). They were subsequently tested on a purpose built experimental boiler and the combustion efficiency was assessed in terms of gaseous emissions and chemical composition of the bottom and fly ashes. The paint dust waste was delivered by a local surface treatment company and characterized concerning chemical, physical and eco toxicological properties, proving to be rich in Carbon (50.2%) and Hydrogen (4.73%). The obtained RDFs were characterized for mechanical durability, elemental and chemical analysis, bulk density and lower heating value. Results show that the utmost lower heating value (19670 kJ/kg) was obtained for the maximum incorporation content of paint dust waste tested (3%). Combustion trials were carried out at a fuel flow rate between 2 and 3 kg/h. The results showed that the incorporation of paint dust waste resulted in a decrease of the thermal efficiency which suggests that the air fuel ratio was not properly adjusted to the varying heat value of the fuel blend. For all the tests, the mass flow rate and the quality of the gaseous emissions were evaluated for the most relevant pollutants such as particles, SO2, TOC, CO and NOx. All parameters, except for particles in one single case, comply with strict environmental limits applicable. Samples of ashes have also been collected and their chemical composition correlated with the fusibility behavior. The results show that such levels of incorporation could be an effective process for paint dust waste management from both the environmental and energetic points of view.